Since the vote to leave, a flurry of working groups with countries including India, Australia and New Zealand have been established in the hope of a post-Brexit trade boost.

Mr Trump is known to speak highly of the Queen, talking of the admiration in which she was held by his mother, and is still expected to enjoy a state visit to Britain - though not until 2018.

Government figures believe they can convince the EU to give them better Brexit terms by showing they are already improving trade with America, signalling the UK has a bright future beyond EU membership.